System and device for controlling thermal gas turbine motive units



I M. H. L. SEDILLE 2,565,796

May 2, 1950 SYSTEM AND DEVICE FOR CONTROLLING THERMAL GAS TURBINE MOTIVEUNITS 2 Sheets-Sheet J.

Original Filed March 16, 1942 am Fig-1 fly N May 2, 1950 M H. SEDILLE2,505,796

SYSTEM ms DEVICE FOR CONTROLLING muz. GAS TURBINE HOTIVE UNITS OriginalFiled larch 16 1942 2 Sheets-Sheet 2 Mom.

Patented May 2, 1950 SYSTEM AND DEVICE FOR CONTROLLING THERMAL GASTURBINE MOTIVE UNITS Marcel Henri Louis Sdilie, Paris, France; vested inthe Attorney General of the United States Original application March 16,1942, Serial No. 434,985, now Patent No. 2,372,686, dated April 3, 1945.Divided and this application February 9, 1994:i Serial No. 576,994. InFrance March Section 1, mu. Law 690, August 8, 1940 Patent expires 10,1961 4 Claims. (CI. 60-41) The present invention relates to gas turbinemotive units the object of which is to supply power or to drive anyreceiving apparatus whatsoever. This application is a division ofcopending application Serial Number 434,985, Patent No. 2,372,686 ofApril 3, 1945. The motive unit may be constituted in any manner andcomprise for example, one or several compressors connected in series orin parallel, with or without intermediary refrigeration, one or severalcombustion chambers, one or several motive or auxiliary turbines with orwithout intermediary reheating, with or without several heat exchangers;the driven apparatus may be an electric generator or any other apparatushaving or not a constant speed.

The invention relates to motive sets having two or more shafts at leastone of which is .used to drive the air compressor or compressors.

In what follows, it will be supposed for the sake of simplifying theexposition, that there are only two shafts, one of which drives thereceiving apparatus, the other driving the air compressor, that there isno regenerator, nor any intermediate reheater between the turbines, norany air refrigerator, these suppositions affecting in no way the scopeof the invention which can be applied also to more complex motive sets.

The object of the present invention is a system for controlling thetemperature in turbines, according to which system the temperature ofthe gases on leaving the first row of mobile blad ing is maintainedconstant, or between two limits or inferior to a given limit, dependentor not on the speed, the said temperature being, in

practice, sufliciently close to the average temperature of the mobileblades themselves and, in any case, dependent on it.

In order to act on the said temperature, while maintaining the powerdelivered by the set at the required value, the invention provides foran increase in the power supplied by the auxiliary turbine, so that thecompressor operating at a higher speed delivers more air and thetemperature of the gases falls; moreover the fuel supply issimultaneously adjusted to maintain the power delivered.

From the viewpoint of yield, it is desirable that the operating point ofthe compressor remain as close as possible .to the maximum yield foreach speed; certain devices which also constitute the object of thepresent invention obtain this result.

The description which follows with reference to the appended drawingsgiven by way of mm 2 limitative example, will indicate how the inventioncan be embodied, those peculiarities which appear in the drawings aswell as in the text being of course a part thereof.

Figs. 1, 2, 3, 4, 5, 6 and 7 show a few nonlimitative embodiments of theinvention.

Fig. 1A is a detail view illustrating the manner of locating a thermalresponsive element immediately behind the first row of mobile blades ofthe turbines.

Fig. 1 represents a turbine motive unit in which the motive turbine Tmand the auxiliary turbine Ta are arranged in parallel. The unitcomprises only one combustion chamber Ch, the load regulator of themotive turbine, which is in this case supposed to be a speed governor R1but which could be a regulator of any other kind, acts on th supply offuel furnished to burner b. It being supposed that the turbine the mostexposed to rises in temperature is the motive turbine Tm, a thermostatt1 maintains at a constant value the temperature of the gases leavingthe first row of mobile blading tb of this turbine by simultaneouslyacting on the obturators O1 and 02 which afiect only a fraction of thegas current passing through each one of the turbines Ta and Tm.

If, for example, the temperature, after the first row of mobile bladingof the turbine Tm, has a tendency to increase, the thermostat t1 opensO: on the feed end of the auxiliary turbine and shuts 01 on the feed endof the motive turbine; the auxiliary turbine accelerates and thecompressor furnishing a greater air supply, the temperature of the gasesfalls. The respective simultaneous positions of the obturators Or and 02can be calculated or determined experimentally in order to maintain thecompressor C at its maximum yield for its new equilibrium speed. Theload governor R1 maintains the power delivered by the unit at therequired value by acting on the fuel supply.

In the embodiment shown in Fig. 2, the turbines Tm and Ta are set inseries, it being supposed that the motive turbine Tm is the highpressure turbine. The governor Rr acts as before on burner b, and thethermostat ti on the obturators O1 and O2 whichaffect only a portion ofthe gas current passing through each turbine. when the temperature ofthe gases leaving the first row of mobile blading of the turbine Tm hasa tendency to rise, the thermostat closes the obturator 0a and opens theobturator 01. The thermal drop in the turbine Tm has a tendency todiminish and that in the turbine To a tendency to increase; thecompressor accelerates and thereby delivers a greater air supply and thetemperature of the gases diminishes. As before, the governor R1 controlsthe fuel consumption by maintaining the power delivered by the turbineTm at the required value. Th respective simultaneous positions of theobturators O1 and 02 may be experimentally calculated or determined inorder to maintain the compressor C at its optimum yield for its newequilibrium speed.

In the embodiment shown in Fig. 3 the constituent parts of the motiveunit have the same layout as in the preceding figure; the control iseffected by by-passing a certain quantity of gas to the turbine Ta,through by-pass B, a quantity which is controlled by the obturator O1 inthe by-pass B dependent upon the thermostat t1.

Of course the same devices can be provided if the high pressure turbineis the auxiliary turbine and the low pressure turbine the motiveturbine.

In the embodiment shown in Fig. 4 where the turbines are, by way ofexample, connected in series, the control is obtained by an electricgenerator G mounted on the shaft of the motive turbine Tm and by anelectric motor M mounted on the auxiliary shaft and receiving its powerfrom the generator G by means of a regulator device for varying theexcitation of the generator G for example controlled by the thermostatT1. If the temperature reaches an inadmissible value in the turbine Tm,the generator G, as a result of the action of the thermostat ti,supplies more power to the motor M which condition results in anincrease in the air supply delivered by the compressor; simultaneouslythe governor R1 reestablishes the power at the required value; of coursethis arrangement can also be used if the high pressure turbine is theauxiliary turbine and if the turbines are connected in parallel.

Fig. 5 represents an embodiment in which the turbines are connected inseries; the thermostat t1 in turbine Ta and the speed detector R2operated by turbine Ta, both act on the position of the obturators O1and 02 of the turbines Tm and Ta, respectively, by means of aswingle-tree p. In this embodiment, the control of the obturators Or and02 of the turbines Tm and Ta, respectively, is effected by the combinedoperation of the thermostat t; sensitive to temperature change in theturbine Ta, and the governor R2 sensitive to the speed of the turbine Taaffected by the fuel control by governor R1 variable accordin to theload on turbine Tm.

. In all the above examples, the motive unit has only one combustionchamber.

livery end of the first mobile biading of the auxiliary turbine andcombined, for example by means of a swingle-tree p: with an organRzsensitive to the speed of the auxiliary group, actuates the other branchof the swingle-tree 1):.

When the load diminishes, for example, the

governor R1 reduces the feed of fuel to the burners bi. and 121; theauxiliary group slows down and the temperature at both turbines varies.

If the said temperature has a tendency to rise beyond the limitallowable after the first expansion stage of the turbine Tm, thethermostat ti closes O1 and opens 02 thus causing the auxil iary unit toaccelerate, which unit delivers more air and causes the temperature ofthe gases to drop: likewise, the thermostat t2 and the organ R2sensitive to the speed simultaneously act on the fuel supply to theburner Zn in order to maintain the temperature, after the first xpansionstage'of the turbine Ta, at a value which is a function of the speed. Ifthis temperature rises, z: closes in and the governor R1 reestablishesthe power delivered by opening in; the temperature at the turbine Tmthereby increases, which condition actuates the regulation controlled bythe thermostat t1. When tz acts, it is possible to have it obtain onlyas approximate adjustment of bl and of O1 and 02 so that R1 and ti needonly then to perfect this adjustment.

Naturally, one of the temperature adjustments may exist without theother, in the case where the latter should prove unnecessary.

In the embodiment shown in Fig. '7, the two turbines connected inparallel are fed by the same combustion chamber and their operatingtemperatures may be rendered different by means of a conduit A1 feedingsupplementary fresh air into one of them, the said conduit beingprovided with a regulating valve or damper Oz.

The governor R1 acts on the burner 22, the thermostat ii of the motiveturbine acts on both the obturators O1 and 02: the thermostat t: of theauxiliary turbine the action of which is, for example, corrected by theorgan R2, sensitive to speed, by means of a swingle-tree p'z, controlsthe valve 0:; when the load drops, for example, the governor R1 reducesthe fuel feed to the burner 12; if the temperature at the turbines thenhas a tendency to rise, the thermostat t1 opens 02 and closes O]. whichcauses the auxiliary unit to accelerate and lowers the temperatures.

If in spite of this, the temperature at the turbine Ta is still toohigh, the thermostat t2 opens 03, which lowers the temperature at theauxiliary turbine but simultaneously raises the temperature at themotive turbine; the thermostat ti then enters into action to bring itback again. This action may be limited to a small measure if t: and R2act on O1 and O2 in parallel with T]. in order to obtain an approximateadjustment. The respective simultaneous positions of the three valves01, O2, and 03 may be calculated so that the compressor yield besubstantially amaximum for all loads; naturally the turbine Tm may alsobe provided with an organ sensitive to speed if its speed diminisheswith the load; finally, only one of the two temperature controls canexist.

In all of the above examples, as in all similar examples falling withinthe scope of the invention, one and only one position of the controlorgans utilized corresponds to each load; the said organs are controlledby the thermostats but can be controlled by the load organ of the mainunit itself, that is to say for example by its speed governor when theunit is at a constant speed, on condition that the position of thecontrol organs which maintain the temperature considered constant can becalculated or noted experimentally; it is then possible to completelysuppress the automatic control or to keep it as a safety measure byhaving it act only as a limiting device; the load regulator of themotive turbine can also obtain only an approximate adjustment of theregulation organs described (organs O1, 03) the thermostats then havingonly to perfect this adjustment.

What is claimed is:

1. In a thermal gas turbine motive unit comprising a motive turbinecapable of delivering power, an auxiliary turbine mechanicallyindependent of the motive turbine, each of said turbines having aplurality of rows of mobile blading arranged in series, an aircompressor driven by the auxiliary turbine and supplying air to the saidturbines and a combustion chamber utilized for heating this air beforeits admission into the'turbines, means for feeding fuel to said chamber,and means controlling the dis= tribution of the gas current between theturbines independently of the speed of the turbines, said meansconsisting of an organ sensitive to the temperature of the first row ofmobile blading of one of the turbines and a speed governor driven by themotive turbine for controlling the quantity of fuel fed to thecombustion chamber independently of the temperature of the gas current.

2. In a thermal gas turbine motive unit comprising a motive turbinecapable of delivering power, an auxiliary turbine mechanicallyindependent of the motive turbine, each of said turbines having aplurality of rows of mobile blading arranged in series, an aircompressor driven by the auxiliary turbine and supplying air to the saidturbines and a combustion chamber utilized for heating this air beforeits admission into the turbines, means for feeding fuel to said chamber,and means controlling the distribution of the gas current between thetwo turbines independently of the speed of the turbines, said meansconsisting of a thermostat mounted in one of the turbines after thefirst row of mobile blading of this turbine and struck by the gaseshaving passed through the said mobile blading and a speed governordriven by the motive turbine for controlling the quantity of fuel fed tothe combustion chamber independently of the temperature of the gascurrent.

3. In a thermal gas turbine motive unit comprising a motive turbinecapable of delivering power, an auxiliary turbine mechanicallyindependent of the motive turbine, each of said turbines having aplurality of rows of mobile blading arranged in series, an aircompressor driven by the auxiliary turbine and supplying the combustionair, a combustion chamber receiving a certain quantity of fuel andutilized for heating this air before its admission into the turbines, adevice for distributing the gas currents between the auxiliary turbineand the motive turbine in order to cause the hot gas currents reachingrespectively these turbines to vary, a thermostat placed in one of theturbines after the first row of mobile blading of the said turbine andsensitive to the temperature of the gases having passed through the saidblading, the said thermostat controlling the gas current distributingdevice independently of the speed of the turbines and a speed governoractuated by the motive turbine and controlling the said quantity of fuelsupplied to the said combustion chamber independently of the temperatureof said gas current.

4. In a thermal gas turbine unit comprising a motive turbine capable ofdelivering power, an auxiliary turbine mechanically independent of themotive turbine, each of said turbines having a plurality of rows ofmobile blading arranged in series, an air compressor driven by theauxiliary turbine and supplying the air to the said turbines, acombustion chamber receiving a certain quantity of fuel and utilized forheating this air before its admission into the turbines, a device fordistributing the power 7 between the auxiliary turbine and the motiveturbine, a thermostat placed in one of the tur-' bines after the firstrow of mobile blading of this turbine and struck by the hot gases havingpassed through the said mobile blading, this thermostat controlling thesaid power distributing device independently of the speed of theturbines, and a speed governor actuated by the motive turbine in orderto control the said quantity of fuel supplied to the combustion chamberindependently of the temperature of the hot gases feeding the turbines.

MARCEL HENRI LOUIS SEDILLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,095,991 Lysholm Oct. 19, 19372,219,994 Jung Oct. 29, 1940 2,371,889 Hermitte Mar. 20, 1945 2,372,686Sdille Apr. 3, 1945

